1. Field of the Invention
The present invention relates to an apparatus for controlling light distributions of head lamps, and particularly to an apparatus for controlling light distributions of head lamps which illuminate the front of a vehicle while the vehicle is running.
2. Description of the Related Art
It is known to provide vehicles with head lamps to improve visibility in front of a driver during night or the like. In general, head lamps are attached to both sides of the front end of a vehicle and they illuminate a relatively wide range. Since, however, the head lamps are fixed, there may be cases where the driver continuously visually observes a dark portion out of the illumination range of the head lamps when the vehicle is being driven, e.g., when the vehicle is being turned, so that portions necessary for the driver to watch during driving cannot be brightly illuminated.
To improve driver visibility, an apparatus for controlling light distributions of head lamps has been disclosed in Japanese Patent Application Laid-Open No. 6(1994)-72234 (corresponding to the priority document for U.S. Pat. No. 5,660,454) as an illustrative example. This apparatus includes a vehicle speed sensor, head lamps in which the light distribution composed of beam spread and beam orientation is changeable, a calculating means and a control means. The calculating means calculates a driver's view position which is determined by the distance the vehicle reaches after a predetermined time along a forward roadway, and calculates a deviation angle formed by a running direction of the vehicle and a direction of said driver's view position. The control means controls the light distribution composed of beam spread and beam orientation of said head lamp on the basis of a result of calculations by said calculating means. Accordingly, the head lamps apply the light to the position which will be observed by the driver so that the visibility at the time of driving is ensured.